Electromagnetic car-brake



R. T.'MURRAY & G. M. ALLEN.

(No Model.)

ELECTROMAGNETIC GAR BRAKE.

Patented Sept. 4, 1894.

UNITED STATES PATENT OFFICE.

ROBERT T. MURRAY AND CHARLES M. ALLEN, OF SAN FRANCISCO,

CALIFORNIA.

ELECTROMAGN ETIC CAR-BRAKE.

SPECIFICATION forming part of Letters Patent No. 525,505, dated September 4, 184.

Application filed October 24, 1892.

To all whom/it may concern:

'Be it known that we, ROBERT T. MURRAY and CHARLES M. ALLEN, citizens of the United States, residing in the city and county of San Francisco, State of California, have invented an Improvement in Electromagnetic Car- Brakes; and we hereby declare the following to be a full, clear, and exact description of the same.

Our invention relates to improvements in car brakes for electric or other roads; and it consists in the employment of a powerful electro magnet or magnets through which a direct attraction and frictional resistance may be had with the surface of the track over which the car is passing.

It also consists in certain details of construction which will be more fully explained by reference to the accompanying drawings, in which- Figure 1 is a longitudinal cross section through our car showing the arrangement of a brake. Fig. 2 is a diagram of the wires and their connections with the magnet and switch.

The object of our invention is to provide a brake in which the electro magnet is attracted with any desired degree of force, to the rails over which the car is passing whereby the friction of the brake upon the rail maybe increased to any desired degree independent of the weight of the car.

The device is also useful in the case of electric cars when climbing steepgrades, to increase the tractile force of the wheels by the employment of a strong electro magnet, the armature of which is retained a short distance above the rail but near enough so that v the attraction will act to hold the wheels more firmly in contact with the rails than could be efiected by the weight of the car alone.

In our invention we have shown electro magnets A A mounted upon the car truck, B, which we have in the present case shown for the purpose of illustrating the operation of our invention. These electro magnets are made of any suitable or desired power. We prefer to wind them with wires in independent series, so that the current may pass through one, two, or more of the series, thus increasing the power of the magnet to any desired degree.

Serial No. 449,853. (No model.)

These magnets are mounted upon frames 0 and have guide rods D passing vertically through the ends, upon which they are movable up and down. Each magnet is set over the line of the rails upon which the car passes, at any suitable or convenient point upon the car. In the present case we have shown them mounted between the truck wheels, and they are supported by springs, E E which normally support the magnets, so that the brake shoes which are secured to the lower ends of the magnets, are at a suflicient distance above the surface of the track, where they remain when no current of electricity is passing through the coils. When, however, a current of electricity passes through the coils, the magnet is energized and the attraction between the magnets and the surface of the track draws the brake shoes downward until they are drawn into strong frictional contact with the track. It will be manifest that this friction may be increased to any desired degree by the strength of the current and by the addition of more coils in the series. This may be efiected in various ways. In the present case we have shown these coils of the magnet connected with insulated plates G, G, G by connecting wires H.

Iis a switch lever fulcrumed between these plates which are arranged in series upon opposite sides of the center about which the lever turns, and they are arranged in such a manner with relation to each other that when the switch lever is turned so that the two plates G, G upon opposite sides are coupled together, the coils a will be connected, and the current passing through these will be of a certain strength. By moving the lever so that either plates G, G or G G are connected, the strength of the magnet will be increased at will, while by turning it to the first of the series of plates g upon opposite sides of the center, the current will be cut off from the magnets altogether. When this occurs the springs E which support the magnet carrying frame, will act to raise the brake shoes from the track and leave the car free to run without resistance.

L represents a resistance coil through whic the current passes before entering the mag-- nets, and which reduces the current to the within reach of the motorman.

has openings 10 made vertically through-it, and when the bar is in its normalposition,

propertension for use inthe magnet coils. The switch'leiver I is actuated by a rod M'con necting it with the foot lever N by which the inotorman can operate it by pressing'thenle-fi ver against a collar M upon the rod M, so as to force the latter back and turn the switch lever; This rod M is also moved bya hinged swinging guard O at the front of the-carwhenever the guard strikes an obstruction, so as to throw the switch leverinto proper position to give the necessary amount of power to the magnet for the stop, and theguard is held in this position by a pawl O. This pawl may be released by the action of the foot lever N which when pressed down releases the pawl, and allows the spring Pto force the guard 0 back to its original posi:

tion, when the pressureupon the lever N is;

shaft Q back to the knee leversR, and these; levers acting upon the brake shoes forcethem' down upon the track so as to make the usualfrictional-r brake whichdepends uponthe weight of the, car for its efliciency. This brake may then be used entirely independent,

of the electro magnetic'device.

When the .power of the; magnets isto' be:

used to increase the tractile power ot the wheels in ascending gradients, a stop is em ployed, which consists of a bar m movable horizontally upon supporting guides and connected by a rodn with an actuating lever 0 these openings will stand beneath the adjustable screws q which pass through the top bar of the frame 0 in which the magnetsare fixed. In this position the magnets arefree to move downward to apply the brakes when the magnets are energized.-

If it is desiredto increase the tractile forceupon the wheels, the bar m is moved until the openings p are'out of line with the'screws q. Now when the magnets are energized, they are drawn down toward the tracks, but the screws q strike the bar m, and prevent actual contact between the brake shoes and the rails,

so that while there isa powerful attraction 1 between the magnets-and the-rails, there iszno actual frictional contact.- The screws-q, may, be so adjusted asto stop the magnets and,

brake shoes at any desired distance from the rails.

The bar m- Having thus describcd ouninventiomwhat in, we-elaim as new,-and desire to secureby Letters Patent, is-

1. VA brake for railway cars consisting of vertically moving brake shoes adapted'to form 1; contact with the lineof rails, and an electro magnet which carries the brake shoes and I moveswith them, independent coils surrounding the core of the magnet, said coils being connected in series, and with switch plates 1 arranged about a center, a lever pivoted at w this center and movable to make connection 7 between the various pairs of 'plates'whereby the power of the magnet is increased, diminished or destroyed,- substantially as described.

2. A brake for railway cars consisting of 15 vertically moving brake shoes adapted to forum. contact with the rails, an electro'magnet which carries the brakeshoes,coils surrounding the, core of themagnet which may be connectelh or disconnected to varythe-strength ofv the! magnet, switch plates and a switch lover I, whereby the connections for this purpose are made,a lever N, a connecting rod, and a re-- turning spring whereby the switch lever isactuated, substantially as described. a

3.. A brake for,v railway cars consisting of vertically moving shoes adapted to form'contactwith the rails, an electro magnet which a carries the brake shoesand moves with them i a switch mechanism by which an electric cur- 9dr rent is caused to pass through the coilsof the magnet or is cut off therefrom, a connecting rod and lever whereby the. switch is actuated at will, and a movable guard extendingdown in front of the car and connectedwiththeqg switch actuating mechanism whereby the magnet is energized and the brake. applied V automatically by contact with any obstruo tion, substantially asdescribedfi 4. The swinging guard connected with a reg mechanism wherebythe electron magnet icon-- ergizedwhen the guard strikes an obstruc tion and the connected brakes are-applied, a pawl and ratchet by which it-is .retainedin position to continue the elcctriccnrrentthrongb i rep the magnet, and a foot lever whereby the pawlv is disengaged and the guard allowed toswing back to its normal position, the, electric current being also cut otf from the magnet and the brakes released at the will of the operator, lt: substantially as described.v

In witnesswhereof we have hereunto set our hands.

ROBERT T. MURRAY. CHARLES. -M'. ALLEN.

Witnesses:

DANL. OCONNELL, WILLIAM F. FLIoK. 

